#include<bits/stdc++.h>
using namespace std;

int main(){
    bool isok=true;
    int a,b;
    cin>>a>>b;
    string s;
    cin>>s;
    for(int i=0;i<s.size();i++){
        if(i==a) isok&=s[i]=='-';
        else isok&=isdigit(s[i]);
    }
    cout<<(isok?"Yes":"No")<<endl;
    return 0;
}