diff --git a/src/libthermo/nnparams.c b/src/libthermo/nnparams.c
index 2e59c42..9400320 100644
--- a/src/libthermo/nnparams.c
+++ b/src/libthermo/nnparams.c
@@ -517,7 +517,7 @@ void nparam_CleanSeq (char* inseq, char* outseq, int len)
 //Calculate TM for given sequence against its complement
 double nparam_CalcSelfTM(PNNParams nparm, char* seq, int len)
 {
-	const unsigned long long minus1 = 0xFFFFFFFFFFFFFFFF;
+	const unsigned long long minus1 = 0xFFFFFFFFFFFFFFFFLLU;
 	const double NaN = *((double*)&minus1);
 	double thedH = 0;
 	//double thedS = nparam_GetInitialEntropy(nparm);
@@ -556,7 +556,7 @@ double nparam_CalcSelfTM(PNNParams nparm, char* seq, int len)
 
 double nparam_CalcTwoTM(PNNParams nparm, char* seq1, char* seq2, int len)
 {
-	const unsigned long long minus1 = 0xFFFFFFFFFFFFFFFF;
+	const unsigned long long minus1 = 0xFFFFFFFFFFFFFFFFLLU;
 	const double NaN = *((double*)&minus1);
 	double thedH = 0;
 	//double thedS = nparam_GetInitialEntropy(nparm);