#include<bits/stdc++.h>
using namespace std;
int main()
{

int a,b,f=1;
cin>>a>>b;
string s;
cin>>s;


for(int i=0;i<a;i++)
{
if(!isdigit(s[i]))
{f=0;
break;}

}
for(int i=a+1;i<s.size();i++)
{
if(!isdigit(s[i]))
{f=0;break;}

}
if(s[a]=='-'&&f)
printf("Yes\n");
else
printf("No\n");
}