//Make sure you use c[i] to access the i-th cost
//and do not remove/change the following line
float c[1..8] = [12, 14, 17, 10, 13, 9, 15, 11];
float s[1..8] = [0.02, 0.025, 0.01, 0.05, 0.01, 0.05, 0.02, 0.015];

range N = 1..8;
dvar boolean y[N];
dvar float prop[N];

minimize sum(i in N)  (c[i] * prop[i]) ;

subject to {
    sum(i in N) prop[i] == 1.0;
    sum(i in N) prop[i] * s[i] <= 1.8/100;
    y[1] <= y[3];
    y[4] <= y[6];
    (sum(i in N) y[i]) == 4;
    forall(i in N)
        0 <= prop[i];
    forall(i in N)
        prop[i] >= 0.05 * y[i];
    forall(i in N)
        prop[i] <= y[i];


}