a,b = list(map(int,input().split()))
s = input()
ans = s[a:b]
lengh = a+b+1
match = 0
match += s.count('1')
match += s.count('2')
match += s.count('3')
match += s.count('4')
match += s.count('5')
match += s.count('6')
match += s.count('7')
match += s.count('8')
match += s.count('9')
match += s.count('0')

if len(s) == a+b+1:
    if ans == '-':
        if s.count("-") == 1:
            if match == a+b:
                print("Yes")
            else:
                print("No")
        else:
            print("No")
    else:
        print("No")
else:
    print("No")
