Expression lambda = Tensors.parseExpression("k=gamma/(1+gamma)");
Expression gamma = Tensors.parseExpression("c=gamma");
iK = (Expression) gamma.transform(lambda.transform(iK));
K = (Expression) gamma.transform(lambda.transform(K));
S = (Expression) gamma.transform(lambda.transform(S));
W = (Expression) gamma.transform(lambda.transform(W));
M = (Expression) gamma.transform(lambda.transform(M));
OneLoopInput input = new OneLoopInput(4, iK, K, S, W, N, M, F);
OneLoopCounterterms action = OneLoopCounterterms.calculateOneLoopCounterterms(input);