s = input ().split() #numero de sttar recen nacidos
h = int(input()) #numero de horas de experimento
 
#depois tu vê como coloca pra receber dois valores com espaço
 
lista = [] #lista com os dados do experimento (vetor dinâmico)
 
tot = s #saída
 
lista.append(s)
lista.append(0)
lista.append(0)
lista.append(0)
lista.append(0)
#primeiros elementos da lista
 
if h>= 3:
    lista[3] = lista[0]*3
    tot += lista[3]
 
#for utilizando função range para percorrer a lista com iteradores, ele começa no 4 e para quando for igual a h+1
for x in range(4, h + 1):
    lista[x] = lista[x-4]*3 + lista[x-3]*3
    tot -= lista[x-4]
    tot += lista[x]
    lista.append(0) #próximo elemento do vetor a ser calculado alocado em tempo de execução
 
print(tot)
 
#eu tentei copiar a lógica do teu algorítmo, mas as saídas estão dando errado
 
 
"""
#include <bits/stdc++.h>
using namespace std;
 
long long int nas[10010];
 
int main (){
	int s, h;
	cin  >> s >> h;
	int i;
 
	nas[0] = s;
 
	long long int tot = s;
 
	if(h>=3){
	nas[3] = nas[0]*3;
	tot += nas[3];
	}
 
	for(i=4;i<=h;i++){
		nas[i] = nas[i-4]*3 + nas[i-3]*3;
		tot -= nas[i-4];
		tot += nas[i];
	}
 
	cout << tot << endl;
}
"""

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