#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, i;
  cin >> A >> B;
  string s;
  cin >> s;
  for (i = 0; i < s.length(); i++) {
    if (i == A && s[i] == '-') continue;
    if (s[i] - '0' >= 0) continue;
    printf("No\n");
    return 0;
  }
  printf("Yes\n");
  return 0;
}
