#include <bits/stdc++.h>
using namespace std;
const int dirx[] = {-2, -1, 1, 2, 1, -1};
const int diry[] = {0, 1, 1, 0, -1, -1};
inline void debugMode() {}
int n, a[100100], b;
string s;
bool u = 1;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> b;
  cin >> s;
  if (s.size() != n + b + 1) return cout << "No", 0;
  for (int i = 0; i < s.size(); i++) {
    if (i == n + 1)
      u &= (s[i] == '-');
    else
      u &= (s[i] >= '0' && s[i] <= '9');
  }
  if (u)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
