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

int find_first_position(char str[], int n, char target) { for (int i = 0; i < n; i++) { if (str[i] == target) { return i; } } return -1; }

int main() { int n; scanf("%d", &n);

char str[10001]; scanf("%s", str);

char target; scanf(" %c", &target);

int position = find_first_position(str, n, target); printf("%d\n", position);

return 0;

}