a,b=map(int,input().split())
s=input()
ans=0
for i in range(a+b+1):
    if i==a and s[i]=="-":
        ans+=1
        print("a")
    elif i!=a and s[i].isdecimal()==True:
        ans+=1
if ans==a+b+1:
    print("Yes")
else:
    print("No")