1753. Maximum Score From Removing Stones

You are playing a solitaire game with three piles of stones of sizes a​​​​​​, b,​​​​​​ and c​​​​​​ respectively. Each turn you choose two different non-empty piles, take one stone from each, and add 1 point to your score. The game stops when there are fewer than two non-empty piles (meaning there are no more available moves).

Given three integers a​​​​​, b,​​​​​ and c​​​​​, return the maximum score you can get.

class Solution {
public:
    int maximumScore(int a, int b, int c) {
        if(!b and !c) return 0;
        if(a < b) return maximumScore(b,a,c);
        if(a < c) return maximumScore(c,b,a);
        if(b < c) return maximumScore(a,c,b);
        return 1 + maximumScore(a-1,b-1,c);
    }
};