You are given a string representing a sequence of N arrows, each pointing in one of the four cardinal directions: up ('^), down (v'), left (*) or right (>'). Write a function solution that, given a string S denoting the directions of the arrows, returns the minimum number of arrows that must be rotated to make them all point in the same direction. Assume that: N is an integer within the range [1..100); string S is made only of the following characters: "^" "v". "<" and/or"s Example: Given S= "v>>>w"

def solution(S):
    # write your code in Python 3.6
    up = 0
    down = 0
    left = 0
    right = 0
    for i in S:
        if i == "v":
            down += 1
        if i == "^":
            up += 1
        if i == "<":
            left += 1
        if i == ">":
            right += 1
    return min(left, right) + min(up, down)