#include <bits/stdc++.h>
using namespace std;
int a, b, k;
int main() {
  scanf("%d%d", &a, &b);
  for (int i = 1; i <= a + b + 1; i++) {
    char c;
    cin >> c;
    if (k == 0) {
      if (i != a + 1)
        if (c < '0' || c > '9')
          k = 1;
        else if (c != '-')
          k = 1;
    }
  }
  if (k)
    printf("No");
  else
    printf("Yes");
  return 0;
}
