#define Z(i)for(X[i]=X[i-1]+1;X[i]<31;X[i]++) B[99],V[4],X[4],T=98,R,i,r;main(j){scanf("%d%d%d%d",V,V+1,V+2,V+3);R=T;Z(1)Z(2)Z(3){for(j=-1;++j3&&R>r?r:R;}R=!printf("%d\n",R);}