 Complete the following phrase:  After the First World War, the 53rd Sikhs were grouped with the 51st, 52nd and 54th Sikhs, and the two battalions of Guides Infantry to form the 12th Frontier Force Regiment in 1922. The 53rd Sikhs became 3rd Battalion Sikhs of the new regiment. For their excellent performance during the First World War, they were made a Royal battalion in 1935. During the Second World War, 312 FF served with great distinction in the Italian East Africa, Sicily, Italy and 