SUBROUTINE SECOND_MEMBRE(N,M,F,COORD,MESH,SECOND_M)
      IMPLICIT NONE
      INTEGER  N,M,I,X1,Y1,X2,Y2,X3,Y3,A,B,C,D
      REAL J,F
      INTEGER  MESH(6*N*M)
      REAL COORD(2*(N+1)*(M+1)),SECOND_M((N+1)*(M+1))

      !Fonction qui crée le second membre

      DO 1 I=1,(N+1)*(M+1)
         SECOND_M(I)=0
 1    CONTINUE

      DO 2 I=1,6*M*N-2,3
      X1=COORD(2*(MESH(I)-1)+1)
      Y1=COORD(2*MESH(I))
      X2=COORD(2*(MESH(I+1)-1)+1)
      Y2=COORD(2*MESH(I+1))
      X3=COORD(2*(MESH(I+2)-1)+1)
      Y3=COORD(2*MESH(I+2))
      A=X2-X1
      B=X1-X3
      C=Y1-Y2
      D=Y3-Y1
      J=A*D-C*B
      SECOND_M(MESH(I))=SECOND_M(MESH(I))+J*F/6
      SECOND_M(MESH(I+1))=SECOND_M(MESH(I+1))+J*F/6
      SECOND_M(MESH(I+2))=SECOND_M(MESH(I+2))+J*F/6
 2    CONTINUE

      END