#include<bits/stdc++.h>
#define rep(i,a,n) for(int i=a;i<n;i++)
using namespace std;

int main(){
  int A,B;
  string S;
  cin >>A>>B>>S;
 
  string ans = "Yes";
  rep(i,0,A) if(S[i]=='-') ans = "No";
  if(S[A]!='-') ans = "No";
  rep(i,A+1,A+B+1) if(S[i]=='-') ans = "No";
  
  cout <<ans<< endl;
}