#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <gmp.h>

/* we can pack the pairs into integers… */
#define P(a,b) (( (a-'A')<<6 )| (b-'A'))

/* …and use them as keys for a lookup table */
enum {maxk=P('Z'+1,'Z')};
MP_INT counts[maxk], tcounts[maxk];

void pcounts(int c) {
    int i,k;
    MP_INT min,max,n;
    mpz_init(&min);
    mpz_init(&max);
    mpz_init(&n);
    for(i='A';i<='Z';i++) {
        k=P(i,'z');
        mpz_set(&n, &counts[k]);
        if (mpz_cmp_ui(&n,0)){
            if (!mpz_cmp_ui(&min,0))
                mpz_set(&min,&n);
            if (mpz_cmp(&n, &min) < 0) mpz_set(&min,&n);
            else if (mpz_cmp(&n, &max) > 0) mpz_set(&max,&n);
        }
    }
    mpz_sub(&n, &max, &min);
    char *r = mpz_get_str(NULL, 10, &n);
    size_t rlen = strlen(r);
    if (rlen > 20)
        printf("%d iterations: %lu digits %.10s...%s\n", c, rlen, r, r+(rlen-10));
    else
        printf("%d iterations: %s\n", c, r);
    free(r);
    mpz_clear(&min);
    mpz_clear(&max);
    mpz_clear(&n);
}

int main(int argc, char **argv) {
    char tmpl[128], rules[128][3]={0};
    int i,j,k, maxiter=40;
    MP_INT n;

    if (argc > 1)
        sscanf(argv[1], "%d",&maxiter);

    mpz_init(&n);
    for(i=0;i<maxk;i++){
        mpz_init(&counts[i]);
        mpz_init(&tcounts[i]);
    }

    scanf("%127[A-Z]\n", tmpl);
    for(i=0;tmpl[i];i++){
        /* set initial counts for pairs and single chars */
        if(i)
            mpz_add_ui(&counts[P(tmpl[i-1],tmpl[i])],&counts[P(tmpl[i-1],tmpl[i])], 1);
        /* use the same LUT for both */
        mpz_add_ui(&counts[P(tmpl[i],'z')],&counts[P(tmpl[i],'z')], 1);
    }

    for(i=0;scanf("%c%c -> %c\n",
                  &rules[i][0], &rules[i][1], &rules[i][2])==3;i++);

    for(i=0;i<maxiter;i++) {
        /* reset temp LUT */
        for(j=0;j<maxk;j++){
            mpz_set_ui(&tcounts[j],0);
        }

        /* apply each rule */
        for(j=0;rules[j][0];j++) {
            k=P(rules[j][0],rules[j][1]);
            mpz_set(&n, &counts[k]);

            if (mpz_cmp_ui(&n,0)) {
                mpz_set_ui(&counts[k],0);
                /* single chars can be updated here */
                k=P(rules[j][2],'z');
                mpz_add(&counts[k],&counts[k], &n);
                /* pairs must be counted independently */
                k=P(rules[j][0],rules[j][2]);
                mpz_add(&tcounts[k],&tcounts[k],&n);
                k=P(rules[j][2],rules[j][1]);
                mpz_add(&tcounts[k],&tcounts[k],&n);
            }
        }

        /* commit temp results */
        for(j=0;rules[j][0];j++) {
            k=P(rules[j][0],rules[j][2]);
            mpz_set(&counts[k], &tcounts[k]);
            k=P(rules[j][2],rules[j][1]);
            mpz_set(&counts[k], &tcounts[k]);
        }

        if (i==maxiter-1) {
            pcounts(i+1);
        } else if (!((i+1)%500)) {
            printf("\033[G%.0f%\033[G",((i+1.0)/maxiter)*100);
            fflush(stdout);
        }
    }
    mpz_clear(&n);
}