gender = input('Enter gender: ','s');
age = input('Enter age: ');
rhr = input('Enter rhr: ');
level = input('Enter level: ','s');
switch gender
    case 'male'
    switch level
        case 'low'
            thr = (220-age-rhr)*0.55+rhr;
        case 'medium'
            thr = (220-age-rhr)*0.65+rhr;
        otherwise
            thr = (220-age-rhr)*0.8+rhr;
    end
    otherwise
    switch level
        case 'low'
            thr = (206-0.88*age-rhr)*0.55+rhr;
        case 'medium'
            thr = (206-0.88*age-rhr)*0.65+rhr;
        otherwise
            thr = (206-0.88*age-rhr)*0.8+rhr;
    end
end
fprintf('THR is %g \n',thr)