How can I use for loop to sum some numbers for a certain time?

I want to sum a set of numbers (10 numbers in the set) for a certain time (user input)

My code is

time = input('Put numbers HERE. ');
CostTotal = 0;
for n = 1:1:time
    Cost = [12 21 45 50 13 11 10 77 89 100];
    CostTotal = CostTotal + Cost;
end

What I want is, if I put 4 as input, it calculates 12+21+45+50.

Thank you for your help.

Answer 1

[Walter Roberson]

time = input('Put numbers HERE. ');
CostTotal = 0;
Cost = [12 21 45 50 13 11 10 77 89 100];

for n = 1:1:time
    CostTotal = CostTotal + Cost(n);
end