566.cpp

#include <stdio.h>
#include <algorithm>
#include <cstdint>

typedef int16_t Int;

Int solveSlow(Int max1, Int max2, Int max3, Int perShirt) {
    static Int maxShirts[128][128][128];
    for (Int n1 = 0; n1 <= max1; ++n1) {
        for (Int n2 = 0; n2 <= max2; ++n2) {
            for (Int n3 = 0; n3 <= max3; ++n3) {
                auto& maxSh = maxShirts[n1][n2][n3];
                maxSh = 0;
                Int from = std::min(n3, Int((perShirt+2)/3));
                Int to = std::max(Int(0), Int(from-2));
                for (Int last3 = from; last3 >= to; --last3) {
                    Int rem = std::max(Int(0), Int(perShirt-3*last3));
                    Int min2 = std::min(n2, Int(rem / 2));
                    Int max2 = std::min(n2, Int((rem+1)/2));
                    for (Int last2 = min2; last2 <= max2; ++last2) {
                        Int last1 = std::max(Int(0), Int(perShirt-3*last3-2*last2));
                        if (last1 <= n1) {
                            maxSh = std::max(maxSh,Int(maxShirts[n1-last1][n2-last2][n3-last3]+1));
                        }
                    }
                }
            }
        }
    }
    return maxShirts[max1][max2][max3];
}

int main() {
    int n1, n2, n3, perShirt;
    scanf("%d %d %d %d", &n1, &n2, &n3, &perShirt);
    printf("%d", solveSlow(n1, n2, n3, perShirt));
    return 0;
}