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

long int solve(int N, int R, int C) {
	long int risp;
	risp=C*(R-C+1);
	return risp;
}

int main() {
    int N, R, C;
    assert(3 == scanf("%d %d %d", &N, &R, &C));
    printf("%llu\n", solve(N, R, C));
    return 0;
}