#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main(int argc, char const *argv[]) {
  int a, b;
  string s;
  std::cin >> a >> b >> s;
  bool ans = true;
  if (s[a] != '-') ans = false;
  for (int i = 0; i < a; i++) {
    if (s[i] > '9') ans = false;
  }
  for (int i = a + 1; i < a + b + 1; i++) {
    if (s[i] > '9') ans = false;
  }
  if (ans)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
