How can I calculate sensitivity and specificity for a given data set after clustering (data is labeled)?

Hi,

I have a labeled data set, each data point represented by a vector of (x,y, label).

I want to claculate sensitivity and specificity after clustering. I attached a sample of the data set.

                  11.08896656  14.57772789  1
                  3.89601932  5.232698948  1
                  5.818664174  11.38813575  1
                  6.836786602  10.72070047  1
                  8.733492848  8.011364398  1
                  10.38458226  -21.94666753  2
                  9.188199574  -16.02884057  2
                  14.6964252  -14.29763491  2
                  -28.68182061  11.03900494  3
                  -31.50790544  13.54812571  3
                  -26.68598993  12.98878238  3
                  -27.50492988  13.37915216  3
                  -26.08960585  14.9192861  3
                  -26.51580637  17.63201417  3
                  -30.61630755  11.3418456  3
                  -30.6416569  -15.66278453  4
                  -28.68622808  -15.19506909  4
                  -34.61944619  -16.85232936  4
                  -29.02861844  -15.50339455  4
                  -25.6794323  -17.13173393  4
                  -31.78782313  -14.25939683  4
                  -26.24932795  -14.748888  4

What is the simplest way to calculate sensitivity and specificity? after performing fuzzy c-mean clustering and k-means clustering