#include <bits/stdc++.h>
using namespace std;
int A, B;
string S;
string solve() {
  int i = 0, j = 0;
  if ((1 <= A) && (B <= 5))
    for (i = 0; (i < (A + B + 1)) && ((S[i] = '-') && (i == A)) &&
                (('0' <= S[i]) && (S[i] <= '9') && (i != A));
         i++)
      ;
  return (i == (A + B)) ? "Yes" : "No";
}
int main() {
  cin >> A >> B >> S;
  cout << solve() << endl;
}
