Find 22 of the same kind (letters are orthogonal connected, not diagonal).
After that, reveal the 23th one.
CSV:
,,,,,,,,,U,S,I,P,O,S,A,S,I,G,G
,,,,,,,,,H,E,L,I,R,T,H,U,E,U,E
,,,24,20,18,,,,D,G,R,U,A,M,S,U,T,D,H
,,,16,15,18,,,,E,U,R,T,U,L,F,I,U,E,G
,,,P,22,12,,,,U,U,D,P,E,R,H,S,D,D,I
,,,P,18,N,,,,H,L,I,U,U,I,O,I,U,S,T
,,,14,O,16,,,,T,Y,S,I,N,E,N,S,E,D,U
,,,,,,,,,O,E,D,E,T,B,L,I,S,E,U
,,,,,,,,,M,I,E,U,I,I,L,K,A,S,I
I,U,T,D,S,T,T,E,F,R,A,F,I,E,M,I,X,H,H,D
F,A,B,E,D,T,I,U,U,H,E,T,E,L,E,S,T,P,S,I
A,L,O,R,S,S,H,U,G,L,E,T,M,H,T,A,E,A,P,I
R,L,S,B,O,M,M,F,G,S,R,N,G,C,I,D,H,E,P,L
F,A,L,O,T,U,E,R,K,K,L,I,S,S,T,S,U,R,A,L
S,S,E,Y,L,H,T,I,E,O,L,A,H,S,G,I,P,T,G,O
G,A,T,U,F,R,P,R,B,E,N,P,E,T,O,R,A,U,T,N
I,H,D,H,E,E,E,L,E,U,T,P,M,U,I,D,E,I,L,L
U,E,T,G,I,T,I,S,L,P,A,E,R,L,J,N,R,P,N,A
D,G,T,B,U,T,U,D,E,K,P,G,I,V,L,I,H,O,G,T
D,T,U,E,T,H,E,G,I,S,A,L,L,O,N,A,E,U,G,S