#include <bits/stdc++.h>
int main() {
  int A, B;
  scanf("%d %d", &A, &B);
  getchar();
  char S[A + B + 1];
  scanf("%s", &S);
  if (S[A] == '-') {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
