determining if a value repeats within a vector

I am trying to determine the value of an integer that repeats 3 times within a vector of 5 elements.

I am trying to code Yahtzee with basic MATLAB knowledge, and am stuck.

An example is a vector of [ 1, 2, 3, 1, 1] and I want to be able to verify that there are 3 ones in the vector.

[per isakson]

Try

>> val =[ 1, 2, 3, 1, 1];
>> [N,edges] = histcounts( val, [unique(val),inf] )
N =
     3     1     1
edges =
     1     2     3   Inf
>> edges( N==3 )
ans =
     1
>> 

[William Marble]

Thanks!