#include    <stdio.h>

int main(void)
{
    int days[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    int d;
    int m;
    int n;

    n = 0;
    for (d = 1; d <= 31; d++) {
        m = (d / 10) + (d % 10);
        if (m > 12) {
            continue;
        }
        if (d <= days[(m - 1)]) {
            n++;
        }
    }
    printf("%d\n", n);
    return 0;
}