Ex 16

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



int main() {
    int m, n;
    FILE *f;
    f = fopen("in.txt", "r");
    if (f == NULL) return 0;
    fscanf(f, "%d%d", &n, &m);
    fclose(f);
    f = fopen("out.txt", "w");
    fprintf(f, "%d", m * n -1);
    fclose(f);
    return 0;
}