sum and if combination in a formula

Hello all, I have three columns of data, each column will have a value of either zero or one

Column 1 Column 2 Column 3
1 0 1

In Column 4, I would like to have a simple formula that sums up the values in columns 1-3; if that value is greater than 2 I would like Column 4 to display the value yes, otherwise, I would like column 4 to display the value "no"
Any help?
Yours,
Simon Kiss