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