function nd = days(mo,da,leap)

nd = 0;

for m = 1:mo-1
    switch m
        case {1, 3, 5, 7, 8, 10}
            nday = 31;
        case {4, 6, 9, 11}
            nday = 30;
        case 2
            nday = 28+leap;
    end
    
    nd = nd+nday;
end

nd = nd+da;