#include<iostream>
using namespace std;
long long int a,b,s;
int main()
{
    string s;
    cin>>a>>b;
    cin>>s;
    if(s[a]!='-')
        cout<<"No"<<endl;
        return 0;
    s[a]='1';
    for(int i=0;i<=a+b;i++)
        if(s[i]<'0'||s[i]>'9')
            cout<<"No"<<endl;
            return 0;
    cout<<"Yes"<<endl;
    return 0;