A,B = map(int,input().split())
s = input()
ans = "Yes"
for i in range(A+B+1):
    if 0 <= i < A or A < i <= B:
        if s[i] not in "1234567890":
            ans = "No"
            break
    if i == A:
        if s[i] != "-":
            ans = "No"
            break
if len(s) != A+B+1:
    ans = "No"
print(ans)
