The Excel function: XOR

Returns a logical exclusive OR of all arguments.

More information:

Other functions
Returns TRUE if all of its arguments are TRUE
Returns the logical value FALSE
Specifies a logical test to perform
Returns a value you specify if a formula evaluates to an error; otherwise, returns the result of the formula
Returns the value you specify if the expression resolves to #N/A, otherwise returns the result of the expression
Checks whether one or more conditions are met and returns a value that corresponds to the first TRUE condition
Reverses the logic of its argument
Returns TRUE if any argument is TRUE
Evaluates an expression against a list of values and returns the result corresponding to the first matching value If there is no match, an optional default value may be returned
Returns the logical value TRUE