#include <stdio.h>

// 以下，正の整数向け
// verified with: yukicoder No.1128 Wedding Ceremony

// int tmp, var = 0; を先に宣言する
#define rd_int(var, tmp)                                                                                               \
    for (;;) {                                                                                                         \
        tmp = getc_unlocked(stdin);                                                                                    \
        if (tmp < '0' || tmp > '9') break;                                                                             \
        var = var * 10 + tmp - '0';                                                                                    \
    }

// char buf[9]; int ptr = 0; を先に宣言する
#define wt_int(var, buf, ptr)                                                                                          \
    while (var) {                                                                                                      \
        buf[ptr++] = var % 10;                                                                                         \
        var /= 10;                                                                                                     \
    }                                                                                                                  \
    while (ptr--) putc_unlocked(buf[ptr] + '0', stdout);

// 以下，負の数もOKなバージョン
// verified with: yukicoder No.1132 凸凹

// int tmp, var = 0, sign = 0; を先に宣言する
#define rd_int_s(var, tmp, sign)                                                                                       \
    for (;;) {                                                                                                         \
        tmp = getchar_unlocked();                                                                                      \
        if (tmp == '-') {                                                                                              \
            sign = 1;                                                                                                  \
            break;                                                                                                     \
        } else if ('0' <= tmp && tmp <= '9') {                                                                         \
            var = tmp - '0';                                                                                           \
            break;                                                                                                     \
        }                                                                                                              \
    }                                                                                                                  \
    for (;;) {                                                                                                         \
        tmp = getc_unlocked(stdin);                                                                                    \
        if (tmp < '0' || tmp > '9') break;                                                                             \
        var = var * 10 + tmp - '0';                                                                                    \
    }                                                                                                                  \
    if (sign) var = -var;

// char buf[9]; int ptr = 0, sign = 0; を先に宣言する
#define wt_int_s(var, buf, ptr, sign)                                                                                  \
    if (var < 0) {                                                                                                     \
        sign = 1;                                                                                                      \
        var = -var;                                                                                                    \
    }                                                                                                                  \
    while (var) {                                                                                                      \
        buf[ptr++] = var % 10;                                                                                         \
        var /= 10;                                                                                                     \
    }                                                                                                                  \
    if (!ptr) buf[ptr++] = 0;                                                                                          \
    if (sign) putc_unlocked('-', stdout);                                                                              \
    while (ptr--) putc_unlocked(buf[ptr] + '0', stdout);

#define rd_int_s_(var, tmp, sign)                                                                                      \
    var = sign = 0;                                                                                                    \
    rd_int_s(var, tmp, sign);

#define wt_int_s_(var, buf, ptr, sign)                                                                                 \
    ptr = sign = 0;                                                                                                    \
    wt_int_s(var, buf, ptr, sign);

int main() {
    long long n = 0;
    int k, ptr = 0;
    char buf[20];

    rd_int(n, k);

    if (n < 10) {
        putc_unlocked('0', stdout);
        return 0;
    }

    int ans = 0;
    while (n >= 10) {
        long long prod = 1;
        while (n > 0 && prod > 0) {
            prod *= (n % 10);
            n /= 10;
        }
        ans++;
        n = prod;
    }
    wt_int(ans, buf, ptr);
    return 0;
}