Counter

def check(s,c,n):
#@param:
#   s: str;
#   c: str;
#   n: int;
#   return: bool;
    assert len(c)==1, "Invalid parameter, c lenght is not 1."
    assert len(s)>=1, "Invalid parameters, s lenght is smaller than 1."
    assert n>=0, "Invalid parameter, n is smaller than 0."
    assert n<=len(s), "Invalid parameter, n is bigger than s lenght."
    return counter(s,c)>=n

def counter(s,c):
#@param:
#   s: str;
#   c: str;
#   return: Int;
    if len(s)==0:
        return 0
    elif s[0]==c:
        return 1+counter(s[1:],c)
    else:
        return counter(s[1:],c)