#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  char s[100];
  scanf("%d %d\n%s", &a, &b, &s);
  for (int i = 0; i < a; i++)
    if (s[i] > '9' || s[i] < '0') return cout << "No" << endl, 0;
  if (s[a + 1] == '-')
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
